Project description:This SuperSeries is composed of the following subset Series: GSE6871: Gene expression signatures that predict radiation exposure (human) GSE6873: Gene expression signatures that predict radiation exposure (mouse) Keywords: SuperSeries Refer to individual Series
Project description:Previous work has demonstrated the potential for peripheral blood (PB) gene expression profiling for the detection of disease or environmental exposures. We have sought to determine the impact of several variables on the PB gene expression profile of an environmental exposure, ionizing radiation, and to determine the specificity of the PB signature of radiation versus other genotoxic stresses. Keywords: peripheral blood, gene expression study, radiation reponse We have sought to determine the impact of several variables on the PB gene expression profile of an environmental exposure, ionizing radiation, and to determine the specificity of the PB signature of radiation versus other genotoxic stresses. Neither genotype differences nor the time of PB sampling caused any lessening of the accuracy of PB signatures to predict radiation exposure, but sex difference did influence the accuracy of the prediction of radiation exposure at the lowest level (50 cGy). A PB signature of sepsis was also generated and both the PB signature of radiation and the PB signature of sepsis were found to be 100% specific at distinguishing irradiated from septic animals. We also identified human PB signatures of radiation exposure and chemotherapy treatment which distinguished irradiated patients and chemotherapy-treated individuals within a heterogeneous population with accuracies of 90% and 81%, respectively. Human and Murine samples used in models Peripheral blood was collected from patients prior to and 6 hrs following total body irradiation with 150 to 200 cGy as part of their pre-transplantation conditioning. For additional comparison, peripheral blood was obtained from healthy volunteers and an additional cohort of patients prior to and 6 hrs following the initiation of alkylator-based chemotherapy alone (without radiotherapy).
Project description:Gene expression analysis of peripheral blood leukocytes (PB MNCs) to develop expression profiles that accurately reflect prior radiation exposure. Keywords: Comparative, exposure dosage, C57BI6 Murine Irradiation Studies We have made use of gene expression analysis of peripheral blood mononuclear cells (PB MNCs) to develop expression profiles that accurately reflect prior radiation exposure. Importantly, we demonstrate that expression profiles can be developed that not only predict radiation exposure in mice but also distinguish the level of radiation exposure, ranging from 50 cGy to 1000 cGy. Likewise, a molecular signature of radiation response developed solely from irradiated human patient samples can predict and distinguish irradiated human PB samples from non-irradiated samples with an accuracy of 90%, sensitivity of 85% and specificity of 94%. We further demonstrate that a radiation profile developed in the mouse can correctly distinguish PB samples from irradiated and non-irradiated human patients with an accuracy of 77%, sensitivity of 82% and specificity of 75%. Taken together, these data demonstrate that molecular profiles can be generated which are highly predictive of different levels of radiation exposure in mice and humans. Mouse Dataset only
Project description:After defining a gene expression signature that predicted radiation exposure dose with high accuracy in human peripheral white blood cells irradiated ex vivo, we now demonstrate the predictive power of gene expression signatures in blood from patients undergoing total body irradiation. Using whole genome microarray analysis, we have identified genes that respond to radiation exposure in cancer patients in vivo. A 3-nearest neighbor classifier built from these genes correctly predicted samples as exposed to 0, 1.25 or 3.75 Gy with 94% accuracy even when samples from healthy donor controls were included. The same samples were classified with 98% accuracy using a signature previously defined from ex vivo irradiation data. The samples could also be classified as exposed or not exposed with 100% accuracy using multiple methods. The demonstration that ex vivo irradiation is an appropriate model that can provide meaningful prediction of in vivo exposure, and that the signatures are robust across diverse disease states, is an important advance in the application of gene expression for biodosimetry. Translation of these signatures to a fully automated “lab-on-a-chip” device will enable high-throughput screening for large-scale radiological emergencies, as well as making such tests practical for clinical uses. Radiation induced gene expression was measured in vivo in TBI patients at 4 hours after 1.25Gy exposure or at 24 hours after 3.75Gy exposure with three 1.25Gy split doses (approximately 4 hours apart). A total of 18 TBI patients, diagnosed with a variety of cancers were used in this study. Blood from 14 healthy control individuals was also used for comparison.
Project description:Exposure to high-dose radiation causes life-threatening serious intestinal damage. Histological analysis is the most accurate method for judging the extent of intestinal damage after death. However, it is difficult to predict the extent of intestinal damage to body samples. Here we focused on extracellular microRNAs (miRNAs) released from cells and investigated miRNA species that increased or decreased in serum and feces using a radiation-induced intestinal injury mouse model. A peak of small RNA of 25–200 nucleotides was detected in mouse serum and feces 72 h after radiation exposure, and miRNA presence in serum and feces was inferred. MiRNAs expressed in the small intestine and were increased by more than 2.0-fold in serum or feces following a 10 Gy radiation exposure were detected by microarray analysis and were 4 in serum and 19 in feces. In this study, miR-375-3p, detected in serum and feces, was identified as the strongest candidate for a high-dose radiation biomarker in serum and/or feces using a radiation-induced intestinal injury model.
Project description:There is a current interest in the development of biodosimetric methods for rapidly assessing radiation exposure in the wake of a large-scale radiological event. The initial focus of this work has largely centered on determining the exposure dose to an individual using biological indicators. Gene expression signatures are showing promise for biodosimetric application, but little is known about how these signatures might translate for the assessment of radiological injury in radiosensitive individuals, who comprise a significant fraction of the general population, and who would likely require treatment following lower doses. Using Parp1-/- mice as a model radiation sensitive genotype, we have investigated the effect of this DNA repair deficiency on the gene expression response to radiation. Although Parp1 is known to play general roles in regulating transcription, the pattern of gene expression changes observed 24 h after exposure to a potentially lethal LD50 dose of radiation was remarkably similar in the two genotypes, and indicated similar levels of activation of both the p53 and NFκB radiation response pathways. In contrast, exposure of wild-type mice to a sub-lethal dose that was equal to the LD50 dose given to the Parp1-/- mice, resulted in a reduced gene expression response. Gene expression classifiers trained on the wild-type data correctly identified all wild-type samples as unexposed, exposed to a sub-lethal dose, or exposed to a potentially lethal dose. All unexposed samples from the Parp1-/- mice were also correctly classified, and 80% of the irradiated samples were identified as exposed to a potentially lethal dose. The results of this study suggest that, at least for some genotypes, gene expression has the potential to accurately detect the extent of radiological injury, rather than being useful only as a surrogate of physical radiation dose.
Project description:Objective:Biomarkers of radiation injury are needed in planning therapeutic measures for cancer patients receiving radiation therapy and civilians exposed to nuclear events. Previous research has highlighted the impact of radiation damage, with cancer patients developing acute disorders including radiation induced pneumonitis or chronic disorders including pulmonary fibrosis months after radiation therapy ends. Discovery of biomarkers that predict these injuries will offer the potential to treat people proactively to mitigate this damage and improve quality of life. Recent research has highlighted the potential for messenger RNA (mRNA), microRNA (miRNA), and long non-coding RNA (lncRNA) to be used as radiation biomarkers. Our study focused on the changes in these RNAs at 48h after radiation exposure of mouse lung tissue to define biological pathway changes and determine potential biomarkers. Result: We observed sustained dysregulation of specific mRNAs, lncRNAs, and miRNAs across all doses. We observed gene dysregulation which can be used to develop both markers to identify no-exposure vs radiation exposure including Hba and Hbb mRNA which were dysregulated even at 1 Gy. We also observed genes which can indicate high dose exposure including Cpt1c and Pdk4. Gdf15, and Eda2r, mRNA markers of senescence and fibrosis, were the most significantly upregulated. Only three miRNAs were significantly dysregulated across all radiation doses, with miRNA-142-3p and miRNA-142-5p downregulated and miRNA-34a-5p upregulated. IPA analysis indicated that numerous pathways relevant to immune function, cell proliferation and survival decreased with increasing doses of radiation. This data highlighted early pathways of dysregulation depending on dose of exposure. This data will help with development of treatments and in medical decision-making. Further experiments are planned to develop medical countermeasures based on this early dysregulation.